Risk of hepatitis B infection in health care workers (HCWs) is a serious and well documented problem. Of the estimated 9,500 HCWs who become infected each year, approximately 500-1000 are estimated to become chronic carriers and 200-300 will eventually die from fulminant hepatitis, cirrhosis or liver cancer. The 1991 Occupational Safety and Health Administration (OSHA) requirement to offer the hepatitis B (HB) vaccine to employees at risk for exposure to HB virus has not resulted in universal acceptance of the vaccine. Although the vaccine is the primary means of preventing HB virus infection, only an estimated 44% of high-risk HCWs were immunized as of 1987 (CDC, 1990). Unpublished data (1993) collected by the CDC since the enactment of the OSHA standard indicates that only an estimated 51% of eligible workers have completed the HB vaccine series. However, no research has been published on HB vaccine acceptance by nursing home workers either before or since the enactment of the standard. The objective of this cross-sectional study is to identify the prevalence and predictors of HB vaccine acceptance by nursing home HCWs. The theoretical framework is the Precaution Adoption Process Model which outlines six stages leading to the adoption of self-protective behaviors, such as completing the vaccine series. The specific aims of this study are: (1) Identify a population of nursing home aides in the Baltimore area who have been offered the HB vaccine; (2) Classify those individuals according to the six stages of the model; and (3) Identify the factors associated with each stage of the vaccine acceptance process. The study population (N=1,000) will be a sample of nursing home aides in the Baltimore area who are at risk for exposure to HB virus. Data will be collected by telephone interviews based, in part, on information already obtained through focus groups. Findings will enable the development of effective communication and prevention strategies that are tailored to workers in each of the precaution adoption stages and aimed at increasing hepatitis B vaccination coverage among nursing home HCWs.